Are there papers about automatic punctuation of written text?
It seems like either of those 2 options you listed would work in this situation. It second, in which you have a binary classifier first, would be a bit more efficient at least, as your deeper net(or whatever classifier you use) would not need to deal with as much. 

It looks like you have a decent idea where to go from here, I'm interested to see what happens with this! Update us when you make some progress.